With my current gun I'd never shoot that far. No way I'd take the shot, let alone have any area with enough view distance to see a deer at 400yards. The bullet would just never have enough killing power behind it at that distance in my gun.

Now with a good gun and bullet setup in good hunting conditions, sure I'd take the shot. In most cases though I'd honestly prefer to try a stalk first before taking a long-distance shot. I'm confident with long-distance shots on game with a correct weapon setup and hunting conditions. Give me a .270 WSM or a .300 WSM, a good scope, some good bullets, and time to sight it in at that distance and that'd be a dead deer, unless weather conditions were too poor or some other negative factor that would increase my chances of wounding the deer.